Sources/SophaxChatCore/Storage/CrashLogManager.swift

1// CrashLogManager.swift
2// SophaxChatCore
3//
4// On-device, privacy-respecting error log.
5// Never logs message content or peer identifiers — only error types and context strings.
6// Users can view and voluntarily export the log from Settings when filing a bug report.
7
8import Foundation
9
10public final class CrashLogManager: @unchecked Sendable {
11
12    public static let shared = CrashLogManager()
13
14    private let logFile: URL
15    private let queue   = DispatchQueue(label: "com.sophax.crashlog", qos: .utility)
16
17    private static let maxLines      = 200
18    private static let maxFileSizeB  = 512_000  // 512 KB safety cap
19
20    private static let iso8601: ISO8601DateFormatter = {
21        let f = ISO8601DateFormatter()
22        f.formatOptions = [.withInternetDateTime]
23        return f
24    }()
25
26    // MARK: - Init
27
28    private init() {
29        let appSupport = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
30        let dir = appSupport.appendingPathComponent("sophax_crash_logs", isDirectory: true)
31        try? FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
32        logFile = dir.appendingPathComponent("crash_log.txt")
33    }
34
35    // MARK: - Public API
36
37    /// Log an error with a context label (e.g. "X3DH", "BackupRestore").
38    /// Only the error *type* is recorded — message content is never logged.
39    public func log(_ error: Error, context: String) {
40        let typeName = String(reflecting: type(of: error))
41        let description = error.localizedDescription
42        // Strip anything that looks like a peer ID (hex strings ≥ 16 chars)
43        let sanitized = sanitize(description)
44        append("[ERROR] [\(context)] \(typeName): \(sanitized)")
45    }
46
47    /// Log a plain diagnostic string (must never contain message content or peer IDs).
48    public func log(_ message: String, context: String) {
49        append("[\(context)] \(message)")
50    }
51
52    /// Returns all log entries as a single string for display or export.
53    public func exportableText() -> String {
54        queue.sync {
55            (try? String(contentsOf: logFile, encoding: .utf8)) ?? "(no log entries)"
56        }
57    }
58
59    /// Delete all log entries.
60    public func clear() {
61        queue.async { [logFile] in
62            try? FileManager.default.removeItem(at: logFile)
63        }
64    }
65
66    // MARK: - Private
67
68    private func append(_ body: String) {
69        let timestamp = Self.iso8601.string(from: Date())
70        let line      = "[\(timestamp)] \(body)\n"
71        queue.async { [weak self] in
72            self?.write(line)
73        }
74    }
75
76    private func write(_ line: String) {
77        // Append to file
78        if let data = line.data(using: .utf8) {
79            if FileManager.default.fileExists(atPath: logFile.path) {
80                if let handle = try? FileHandle(forWritingTo: logFile) {
81                    handle.seekToEndOfFile()
82                    handle.write(data)
83                    try? handle.close()
84                }
85            } else {
86                try? data.write(to: logFile, options: .atomic)
87            }
88        }
89        rotate()
90    }
91
92    /// Keep the file under maxLines and maxFileSizeB.
93    private func rotate() {
94        guard let text = try? String(contentsOf: logFile, encoding: .utf8) else { return }
95        var lines = text.components(separatedBy: "\n")
96        // Remove empty trailing element from split
97        if lines.last == "" { lines.removeLast() }
98
99        let oversizedFile = (text.utf8.count > Self.maxFileSizeB)
100        let tooManyLines  = (lines.count > Self.maxLines)
101
102        guard oversizedFile || tooManyLines else { return }
103
104        // Drop oldest half
105        let keep = lines.suffix(Self.maxLines / 2)
106        let trimmed = keep.joined(separator: "\n") + "\n"
107        try? trimmed.write(to: logFile, atomically: true, encoding: .utf8)
108    }
109
110    /// Remove long hex-looking substrings that could be peer IDs.
111    private func sanitize(_ input: String) -> String {
112        // Replace hex sequences of 16+ chars with <redacted>
113        let pattern = "[0-9a-fA-F]{16,}"
114        return (try? NSRegularExpression(pattern: pattern))
115            .map { $0.stringByReplacingMatches(in: input, range: NSRange(input.startIndex..., in: input), withTemplate: "<redacted>") }
116            ?? input
117    }
118}